require 'confusion_matrix'

cm = ConfusionMatrix.new :pos, :neg # the matrix has two classes
cm.add_for(:pos, :pos, 10) # add 10 observations of (:pos, :pos)
3.times { cm.add_for(:pos, :neg) } # add 3 observations separately
20.times { cm.add_for(:neg, :neg) }
5.times { cm.add_for(:neg, :pos) }

puts "Precision: #{cm.precision}" # results for :pos class
puts "Recall: #{cm.recall}"
puts "MCC: #{cm.matthews_correlation}"
puts
puts(cm.to_s)
